| Nombre del plugin | Generador de gráficos Wp |
|---|---|
| Tipo de vulnerabilidad | XSS almacenado autenticado |
| Número CVE | CVE-2025-8685 |
| Urgencia | Baja |
| Fecha de publicación de CVE | 2025-08-11 |
| URL de origen | CVE-2025-8685 |
Aviso de vulnerabilidad: Generador de gráficos WP (≤ 1.0.4) — XSS almacenado de contribuyente autenticado a través del shortcode [wpchart] (CVE‑2025‑8685)
Resumen ejecutivo
Este aviso describe una vulnerabilidad de scripting entre sitios almacenada (XSS) en el plugin de WordPress “WP Chart Generator” (versiones ≤ 1.0.4), rastreada como CVE‑2025‑8685. Un usuario autenticado con privilegios de Contribuyente (o superiores) puede almacenar cargas útiles maliciosas a través del shortcode [wpchart] del plugin. Dado que la carga útil es persistente, los visitantes que vean la página afectada pueden ejecutar JavaScript controlado por el atacante en sus navegadores.
La gravedad se considera baja a media en la divulgación reportada (vector CVSS ~6.5) porque la explotación requiere una cuenta de Contribuyente autenticada. No hay un parche oficial del proveedor en el momento de la publicación. Este aviso proporciona detalles técnicos, métodos de detección, opciones de mitigación a corto plazo, orientación para la remediación de desarrolladores, ejemplos de reglas WAF/ModSecurity y una lista de verificación de respuesta a incidentes desde la perspectiva de un experimentado profesional de seguridad de Hong Kong.
¿Cuál es la vulnerabilidad?
- Software afectado: plugin Generador de gráficos WP
- Versiones afectadas: ≤ 1.0.4
- Tipo de vulnerabilidad: Scripting entre sitios almacenado (XSS) en la representación del shortcode [wpchart]
- Privilegio requerido: Contribuyente (o superior)
- Publicado: 11 de agosto de 2025
- CVE: CVE‑2025‑8685
- Solución oficial: Ninguna en el momento de la publicación
El plugin renderiza atributos de shortcode no confiables y/o contenido interno directamente en HTML/JS del front-end sin la correcta sanitización y escape. Un contribuyente puede crear contenido con un shortcode [wpchart] elaborado que contenga fragmentos de script o controladores de eventos. Cuando se renderiza, el navegador ejecuta el JavaScript inyectado en el origen del sitio.
Por qué es importante (análisis de impacto)
El XSS almacenado sigue siendo de alto riesgo incluso cuando el acceso inicial requiere bajo privilegio. Impactos clave:
- Las cargas útiles persistentes se ejecutan cada vez que los visitantes ven la página, ampliando la exposición.
- El JavaScript ejecutado se ejecuta con los privilegios del origen de la página: puede intentar robar cookies (si no son HttpOnly), realizar acciones en nombre de usuarios autenticados, mostrar una interfaz de phishing o redirigir a los visitantes, y cargar más recursos maliciosos (cadenas de explotación, cargadores, criptomineros).
- Muchos sitios permiten cuentas de contribuyentes (por ejemplo, blogs de múltiples autores, sitios de membresía), por lo que un atacante puede obtener o crear tales cuentas.
- Las cuentas de editor/admin que ven contenido del front-end mientras están conectadas aumentan el riesgo de escalada de privilegios o toma de control de cuentas.
Cómo se ve la explotación: recorrido técnico de alto nivel
El plugin registra un [wpchart] shortcode que acepta atributos (etiquetas, títulos, arreglos de datos, colores). La vulnerabilidad surge cuando estos atributos se incrustan en HTML o JavaScript en línea sin un escape consciente del contexto.
- Un atacante obtiene o crea una cuenta de Contribuyente.
- Agregan una publicación o página que contiene un
[wpchart]shortcode con atributos o contenido interno que lleva fragmentos de script o controladores de eventos. - La carga útil se almacena en la base de datos. Cuando se sirve la página, el navegador analiza el marcado o script inyectado y lo ejecuta.
- Cualquier visitante (incluidos editores/admins conectados) puede activar la carga útil.
Cargas útiles ilustrativas (no desplegar en sitios públicos):
[wpchart title=""]
[wpchart data='[{"label":"
","value":10}]']
La causa raíz es renderizar entradas no confiables en contextos de HTML/JS sin escape o validación.
Escenarios de explotación y quién está en riesgo
- Sitios que permiten a los contribuyentes crear contenido (sitios de membresía o multi-autores).
- Sitios con registro social, autores importados en masa o controles de cuenta débiles.
- Sitios donde editores/admins previsualizan o ven contenido del front-end mientras están autenticados.
- Los visitantes y clientes públicos pueden verse afectados (daño a la privacidad y reputación).
- Los sitios de comercio son particularmente sensibles debido a la posible manipulación de los flujos de pago.
Detección: cómo encontrar instancias vulnerables o explotadas
Buscar publicaciones, páginas y meta para [wpchart] instancias y fragmentos similares a scripts.
WP-CLI
# Buscar publicaciones y páginas para 'wpchart'
SQL
-- Buscar post_content para el shortcode wpchart;
Buscar tokens sospechosos: <script, onerror=, onload=, javascript:, document.cookie, obtener(, y equivalentes codificados (por ejemplo, <script>, %3Cscript%3E).
SELECT ID, post_title, post_content
Also search postmeta and plugin options where chart configurations may be stored:
SELECT post_id, meta_key, meta_value
FROM wp_postmeta
WHERE meta_value LIKE '%wpchart%'
OR meta_value REGEXP '(?i)(
Examine webserver logs for POSTs creating/updating content and for outbound requests to suspicious domains originating from page views.
Short-term mitigations (site owners and admins)
If an immediate vendor patch is unavailable, take the following actions to reduce exposure:
- Remove or deactivate the plugin (preferred): If chart functionality is not required immediately, deactivate and remove the plugin until fixed.
- Restrict Contributor accounts: Temporarily disable new registrations or change default role to Subscriber. Review contributors and suspend or reset passwords for suspicious accounts.
- Review content and remove malicious shortcodes: Search posts/pages and sanitize or remove any
[wpchart]occurrences that include script-like patterns. - Temporary server-side sanitizer (virtual patch): Override the shortcode with a safe handler to sanitize attributes and content. Example mu-plugin snippet:
<?php
// mu-plugin/wpchart-sanitizer.php
if ( ! function_exists( 'wpchart_sanitized_handler' ) ) {
function wpchart_sanitized_handler( $atts = [], $content = '' ) {
// Basic attribute sanitization example
$atts = array_map( 'sanitize_text_field', (array) $atts );
// whitelist numeric attributes
if ( isset( $atts['width'] ) ) {
$atts['width'] = intval( $atts['width'] );
}
if ( isset( $atts['height'] ) ) {
$atts['height'] = intval( $atts['height'] );
}
// sanitize content using a safe allowlist
$content = wp_kses( $content, array(
'a' => array( 'href' => true, 'title' => true ),
'span' => array( 'class' => true ),
) );
// Build safe output (example: escaped)
$title = isset( $atts['title'] ) ? esc_html( $atts['title'] ) : '';
return '<div class="wpchart-safe" data-config="' . esc_attr( json_encode( $atts ) ) . '">' . $title . $content . '</div>';
}
// Remove original shortcode if registered and register safe handler
remove_shortcode( 'wpchart' );
add_shortcode( 'wpchart', 'wpchart_sanitized_handler' );
}
?>
Notes: place this as an mu-plugin so it loads early. This is a temporary mitigation to neutralize stored payloads before rendering.
- Harden browser-side controls: Implement a Content Security Policy (CSP) that blocks inline scripts and restricts script sources. Example header:
Content-Security-Policy: default-src 'self'; script-src 'self' https://trusted-cdn.example.com; object-src 'none'; base-uri 'self'; frame-ancestors 'none'Also ensure cookies use Secure and HttpOnly flags and consider SameSite settings.
- Deploy rule-based request filters: Use host-level or application-layer filters to block content submissions containing script-like payloads targeted at the
[wpchart]shortcode (examples below).
WAF / ModSecurity rules (examples)
Below are example ModSecurity rules to block common XSS patterns related to [wpchart]. Test thoroughly before applying to production.
# ModSecurity example
SecRule REQUEST_URI|REQUEST_BODY "@rx \[wpchart[^\]]*(
SecRule REQUEST_METHOD "^POST$" \
"chain, id:1001002,phase:2,deny,log,status:403,msg:'Blocked POST containing script tag',severity:2"
SecRule REQUEST_BODY "@rx <\s*script\b" "t:none"
SecRule REQUEST_BODY "@rx \[wpchart[^\]]*(onerror|onload|javascript:|document\.cookie|window\.location)" \
"id:1001003,phase:2,deny,log,status:403,msg:'Blocked suspicious attribute inside wpchart',severity:2"
SecRule REQUEST_URI "@rx /wp-admin/post.php|/wp-admin/post-new.php" \
"phase:2,id:1001004,deny,log,status:403,msg:'Blocked potential XSS payload in post content',chain"
SecRule REQUEST_BODY "@rx (onerror|onload|<\s*script|javascript:|document\.cookie|fetch\()" "t:none"
Guidance:
- Target rules narrowly (match the
[wpchart]token and plugin-specific meta keys) to reduce false positives. - Log and run in monitor/report-only mode initially to tune rules, then switch to deny once confidence is established.
- Combine with rate-limiting to mitigate repeated attempts.
Recommended permanent code fixes for plugin developers
Developers should address the root causes with robust validation and context-aware escaping:
- Sanitize input on accept: Use typed validation for numeric fields (intval(), floatval()), use
sanitize_text_field()for simple strings, and parse & validate JSON configuration server-side. - Escape output per context: Use
esc_attr()for attribute values,esc_html()for text nodes andwp_kses()with strict allowlists for any permitted HTML. Avoid echoing unchecked input into inline scripts. - Prefer data-* attributes: Emit sanitized JSON inside a data attribute via
wp_json_encode()and let a vetted client-side script consume that data safely. - Enforce capability checks and nonces: For any AJAX endpoints or admin UI that stores content, enforce
current_user_can()andcheck_admin_referer(). - Example safe shortcode output pattern:
function wpchart_safe_shortcode( $atts = [], $content = '' ) {
$atts = shortcode_atts( array(
'title' => '',
'width' => 600,
'height' => 400,
'data' => '[]',
), $atts, 'wpchart' );
// Sanitize / validate
$safe = array(
'title' => sanitize_text_field( $atts['title'] ),
'width' => intval( $atts['width'] ),
'height' => intval( $atts['height'] ),
);
// For JSON data: decode and validate structure; re-encode safely
$data = json_decode( wp_unslash( $atts['data'] ), true );
if ( ! is_array( $data ) ) {
$data = array();
}
// Validate each data point (example)
$validated_data = array();
foreach ( $data as $row ) {
$label = isset( $row['label'] ) ? sanitize_text_field( $row['label'] ) : '';
$value = isset( $row['value'] ) ? floatval( $row['value'] ) : 0;
$validated_data[] = array( 'label' => $label, 'value' => $value );
}
// Output: store config safely in data attribute and escape it for HTML
$cfg = wp_json_encode( array(
'title' => $safe['title'],
'width' => $safe['width'],
'height'=> $safe['height'],
'data' => $validated_data,
) );
return sprintf(
'<div class="wpchart" data-wpchart="%s"></div>',
esc_attr( $cfg )
);
}
Do not build inline scripts that interpolate user-provided values. Use external, audited JS that reads sanitized data-* attributes.
Incident response: If you suspect exploitation
- Take affected page(s) offline (unpublish) or put the site into maintenance mode if widespread.
- Identify and remove malicious posts, shortcodes or plugin meta entries (see detection section).
- Change passwords for Contributor+ accounts and administrators. Consider forcing password resets for all users if compromise is suspected.
- Inspect server logs for suspicious activity and block attacker IPs at host or WAF level.
- Run a full malware scan and file integrity check. Look for added admin users, unexpected scheduled tasks, or backdoors.
- Rotate API keys, integration tokens, and any stored credentials that could be exposed.
- If admin accounts were compromised, audit site settings and restore from a known-clean backup if necessary.
- Notify affected users if user data may have been exposed, following applicable privacy and breach-notification law.
- After cleanup, re-enable stricter registration policies, enforce two-factor authentication for elevated roles, apply CSP and secure HTTP headers.
- Monitor for re-injection attempts and maintain long-term detection rules.
Monitoring and detection after cleanup
- Enable logging for request filters and review blocked events.
- Set up content integrity checks to detect reappearance of suspicious
[wpchart]shortcodes or injected script tags. - Schedule weekly scans and manual reviews for a period after the incident.
- Deploy updates in a staging environment and validate fixes before production rollout.
Hardening recommendations to reduce XSS risk site-wide
- Apply principle of least privilege: limit Contributor role usage and consider custom roles with reduced capabilities.
- Require editorial review workflows: contributors should submit for review rather than publish directly.
- Enforce strong passwords and two-factor authentication for editors and administrators.
- Restrict untrusted user registration or require administrator approval.
- Use CSP in report-only mode first to identify issues, then enforce once safe.
- Ensure session cookies are HttpOnly and Secure; consider SameSite settings.
- Keep WordPress core and plugins updated and perform periodic security audits.
A short note for developers: test for XSS during QA
- Include input fuzzing for shortcode attributes and stored values.
- Automate tests to detect unescaped outputs in HTML and JS contexts.
- Review third-party chart libraries and ensure data is passed safely (prefer data-* + JSON + validated client-side rendering).
- Maintain a clear disclosure policy and a public changelog to accelerate coordinated fixes when issues are reported.
Frequently asked questions (FAQ)
Q: If I am not using the WP Chart Generator plugin, am I affected?
No. This advisory concerns specifically the WP Chart Generator plugin (≤ 1.0.4). However, the general guidance applies to any plugin that renders unescaped user input.
Q: If an attacker needs a Contributor account, is my site safe?
Not necessarily. Many sites allow registrations that map to low-privilege roles; weak or reused passwords are a common vector. Treat user registration as a potential risk and limit privileges where possible.
Q: Will a Content Security Policy fully prevent exploitation?
A properly configured CSP substantially reduces the impact of many XSS payloads by blocking inline scripts and restricting script origins, but CSP should complement input sanitization and server-side protections — it is not a substitute for correct coding.
Q: Is the issue already patched?
At the time of this advisory, no official patched release was available. Follow the plugin's release channel for updates and apply the mitigations listed here until a patch is published.
Closing thoughts
Stored XSS like CVE‑2025‑8685 can have persistent and far-reaching consequences. Although exploitation requires authenticated access, many realistic paths exist to obtain contributor-level permissions. Treat unescaped shortcode attributes and plugin-rendered client-side scripts as high priority. Immediate actions: review and sanitize content, restrict Contributor capabilities, apply temporary sanitization or request-filtering, and consider deactivating the plugin until it is fixed. Plugin authors should implement strict input validation and context-aware escaping for all shortcode attributes and stored content.
If you lack in-house capability to perform scans or apply mitigations, engage a trusted security practitioner or managed service to assist with detection, virtual patching and recovery steps. Maintain careful logs of remediation actions and preserve forensic artifacts if a compromise is suspected.
Stay vigilant. Review user-generated content regularly and reduce the blast radius of low-privilege user accounts.